The subject invention relates to an improved housing for an electrical resistor. More specifically, the subject invention relates to an improved housing attachment for attaching the housing to a blower casing.
A speed control for a blower motor of a heating, venting, and air conditioning system typically comprises a resistor assembly for resisting the flow of electric current to the blower motor from an electrical circuit. The most widely used type of resistor is a heat dissipater, which is affixed to a blower casing so turbulent air emitted from the blower motor can contact the dissipater. The heat dissipater absorbs energy from the electrical circuit and dissipates it in the form of heat thereby reducing the flow of electrical current to the blower motor. Electrical current is routed through the resistor via a control setting. If the setting is on high blower speed, no electrical current will be routed through the resistor. If the setting is on low blower speed, most of, or all of the current will be routed through the resistor reducing the flow of electrical current to the blower motor thereby reducing the speed of the motor. The resistor assembly includes a housing for encasing the dissipater. The housing includes a seal for providing a leak proof mating surface between the housing and the blower casing.
The housing is typically attached to the blowercasing with self tapping type screw fasteners. These screws provide a leak proof attachment between the housing and the casing. The use of screws also provides for an easy method of removing the resistor from the casing for maintenance or replacement by merely reversing the screw. However, utilizing screws as an attachment means is cost prohibitive due to assembly time and screw cost. In addition, the use of self tapping screws has proven to be an ergonomically difficult operation.
Attempts have been made to replace screws with snap-fit attachments. However, snap-fit attachments do not provide a leak proof seal between the housing and casing unless the snap-fit attachment is completely covered by the housing preventing access to the snap. Absent access to the snap, the housing can not be released from casing for maintenance and replacement.
Therefore, a need exists for snap-fit type attachment of a resistor housing to a blower casing that provides for both a leak proof seal and a for access to the snap for maintenance and replacement.
The present invention relates to an electrical resistor assembly of the type that is affixed to a blower casing of a heating, venting, and air conditioning blower motor. The resistor resists the flow of electricity to the blower motor and includes a heat dissipater for dissipating heat generated by electrical current flowing through the circuit. A connector connects the assembly to the electrical circuit. A housing encases the dissipater and the connector. The housing includes a seal for providing a leak proof mating surface between the assembly and the casing. The housing includes at least one catch for fixedly attaching the assembly to the casing and includes at least one break-away element for providing service access to the catch. The seal traverses the housing, including the catch. The catch provides for a snap-fit attachment of the resistor assembly to the blower casing. Preferably, the assembly will include opposing catches each having an associated break-away element providing access thereto.
The break-away element allows a housing configuration that completely covers the catches. Thus, the housing can include a seal that circumscribes the catches providing a leak proof mating surface with the casing. The break-away element also provides access to the catches enabling the release of the catches from the casing for maintenance or removal of the resistor assembly from the casing.